Hi all, Some nslookup oddities have been bothering me. Does it look to you like my ISP is blocking certain DNS queries?
First, here's what I expect *and* what I get when I SSH to an account at maseru.dreamhost.com: [maseru]$ nslookup debian.org Server: 66.33.216.127 Address: 66.33.216.127#53 Non-authoritative answer: Name: debian.org Address: 206.12.19.7 [...] [maseru]$ nslookup ftp.us.debian.org Server: 66.33.216.127 Address: 66.33.216.127#53 Non-authoritative answer: Name: ftp.us.debian.org Address: 204.152.191.39 [...] Now, let's try querying the *same* nameserver from my home computer via my ISP (hawaiian telecom). $ nslookup google.com 66.33.216.127 Server: 66.33.216.127 Address: 66.33.216.127#53 Non-authoritative answer: Name: google.com Address: 74.125.224.52 [...] $ nslookup debian.org 66.33.216.127 ;; connection timed out; no servers could be reached $ nslookup ftp.us.debian.org 66.33.216.127 ;; connection timed out; no servers could be reached $ nslookup perl.com 66.33.216.127 Server: 66.33.216.127 Address: 66.33.216.127#53 Non-authoritative answer: Name: perl.com Address: 208.201.239.101 [...] I'd like to find some other explanation. This is with my firewall turned off. btw, I get the same issues using my ISPs nameserver via the ethernet modem. $ nslookup google.com 192.168.0.1 Server: 192.168.0.1 Address: 192.168.0.1#53 Non-authoritative answer: Name: google.com Address: 74.125.224.83 [...] $ nslookup debian.org 192.168.0.1 Server: 192.168.0.1 Address: 192.168.0.1#53 ** server can't find debian.org: SERVFAIL Finally, here are the queries (external DNS server, then via ISP's ASDL modem) followed by a corresponding wireshark dump of the network traffic. Thanks for your attention! ------------------------------------------------------------ nslookup google.com 66.33.216.127 # succeeds nslookup debian.org 66.33.216.127 ;; connection timed out; no servers could be reached nslookup google.com 192.168.0.1 # succeeds nslookup debian.org 192.168.0.1 ** server can't find debian.org: SERVFAIL ------------------------------------------------------------ No. Time Source Destination Protocol Info 1 0.000000 192.168.0.105 66.33.216.127 DNS Standard query A google.com Frame 1 (70 bytes on wire, 70 bytes captured) Ethernet II, Src: WistronI_19:e6:be (f0:de:f1:19:e6:be), Dst: AniCommu_c5:4f:19 (00:40:05:c5:4f:19) Internet Protocol, Src: 192.168.0.105 (192.168.0.105), Dst: 66.33.216.127 (66.33.216.127) User Datagram Protocol, Src Port: 47670 (47670), Dst Port: domain (53) Domain Name System (query) No. Time Source Destination Protocol Info 2 0.031068 66.33.216.127 192.168.0.105 DNS Standard query response A 74.125.224.81 A 74.125.224.82 A 74.125.224.83 A 74.125.224.84 A 74.125.224.80 Frame 2 (286 bytes on wire, 286 bytes captured) Ethernet II, Src: AniCommu_c5:4f:19 (00:40:05:c5:4f:19), Dst: WistronI_19:e6:be (f0:de:f1:19:e6:be) Internet Protocol, Src: 66.33.216.127 (66.33.216.127), Dst: 192.168.0.105 (192.168.0.105) User Datagram Protocol, Src Port: domain (53), Dst Port: 47670 (47670) Domain Name System (response) No. Time Source Destination Protocol Info 3 7.417343 192.168.0.105 66.33.216.127 DNS Standard query A debian.org Frame 3 (70 bytes on wire, 70 bytes captured) Ethernet II, Src: WistronI_19:e6:be (f0:de:f1:19:e6:be), Dst: AniCommu_c5:4f:19 (00:40:05:c5:4f:19) Internet Protocol, Src: 192.168.0.105 (192.168.0.105), Dst: 66.33.216.127 (66.33.216.127) User Datagram Protocol, Src Port: 55129 (55129), Dst Port: domain (53) Domain Name System (query) No. Time Source Destination Protocol Info 4 12.417482 192.168.0.105 66.33.216.127 DNS Standard query A debian.org Frame 4 (70 bytes on wire, 70 bytes captured) Ethernet II, Src: WistronI_19:e6:be (f0:de:f1:19:e6:be), Dst: AniCommu_c5:4f:19 (00:40:05:c5:4f:19) Internet Protocol, Src: 192.168.0.105 (192.168.0.105), Dst: 66.33.216.127 (66.33.216.127) User Datagram Protocol, Src Port: 55129 (55129), Dst Port: domain (53) Domain Name System (query) No. Time Source Destination Protocol Info 5 17.417696 192.168.0.105 66.33.216.127 DNS Standard query A debian.org Frame 5 (70 bytes on wire, 70 bytes captured) Ethernet II, Src: WistronI_19:e6:be (f0:de:f1:19:e6:be), Dst: AniCommu_c5:4f:19 (00:40:05:c5:4f:19) Internet Protocol, Src: 192.168.0.105 (192.168.0.105), Dst: 66.33.216.127 (66.33.216.127) User Datagram Protocol, Src Port: 55129 (55129), Dst Port: domain (53) Domain Name System (query) No. Time Source Destination Protocol Info 6 28.176305 192.168.0.105 192.168.0.1 DNS Standard query A google.com Frame 6 (70 bytes on wire, 70 bytes captured) Ethernet II, Src: WistronI_19:e6:be (f0:de:f1:19:e6:be), Dst: AniCommu_c5:4f:19 (00:40:05:c5:4f:19) Internet Protocol, Src: 192.168.0.105 (192.168.0.105), Dst: 192.168.0.1 (192.168.0.1) User Datagram Protocol, Src Port: 47893 (47893), Dst Port: domain (53) Domain Name System (query) No. Time Source Destination Protocol Info 7 28.214736 192.168.0.1 192.168.0.105 DNS Standard query response A 74.125.224.83 A 74.125.224.84 A 74.125.224.80 A 74.125.224.81 A 74.125.224.82 Frame 7 (286 bytes on wire, 286 bytes captured) Ethernet II, Src: AniCommu_c5:4f:19 (00:40:05:c5:4f:19), Dst: WistronI_19:e6:be (f0:de:f1:19:e6:be) Internet Protocol, Src: 192.168.0.1 (192.168.0.1), Dst: 192.168.0.105 (192.168.0.105) User Datagram Protocol, Src Port: domain (53), Dst Port: 47893 (47893) Domain Name System (response) No. Time Source Destination Protocol Info 8 33.652277 192.168.0.105 192.168.0.1 DNS Standard query A debian.org Frame 8 (70 bytes on wire, 70 bytes captured) Ethernet II, Src: WistronI_19:e6:be (f0:de:f1:19:e6:be), Dst: AniCommu_c5:4f:19 (00:40:05:c5:4f:19) Internet Protocol, Src: 192.168.0.105 (192.168.0.105), Dst: 192.168.0.1 (192.168.0.1) User Datagram Protocol, Src Port: 36765 (36765), Dst Port: domain (53) Domain Name System (query) No. Time Source Destination Protocol Info 9 37.456094 66.33.216.127 192.168.0.105 DNS Standard query response, Server failure Frame 9 (70 bytes on wire, 70 bytes captured) Ethernet II, Src: AniCommu_c5:4f:19 (00:40:05:c5:4f:19), Dst: WistronI_19:e6:be (f0:de:f1:19:e6:be) Internet Protocol, Src: 66.33.216.127 (66.33.216.127), Dst: 192.168.0.105 (192.168.0.105) User Datagram Protocol, Src Port: domain (53), Dst Port: 55129 (55129) Domain Name System (response) No. Time Source Destination Protocol Info 10 37.456141 192.168.0.105 66.33.216.127 ICMP Destination unreachable (Port unreachable) Frame 10 (98 bytes on wire, 98 bytes captured) Ethernet II, Src: WistronI_19:e6:be (f0:de:f1:19:e6:be), Dst: AniCommu_c5:4f:19 (00:40:05:c5:4f:19) Internet Protocol, Src: 192.168.0.105 (192.168.0.105), Dst: 66.33.216.127 (66.33.216.127) Internet Control Message Protocol No. Time Source Destination Protocol Info 11 37.457408 72.235.80.4 192.168.0.105 DNS Standard query response, Server failure Frame 11 (70 bytes on wire, 70 bytes captured) Ethernet II, Src: AniCommu_c5:4f:19 (00:40:05:c5:4f:19), Dst: WistronI_19:e6:be (f0:de:f1:19:e6:be) Internet Protocol, Src: 72.235.80.4 (72.235.80.4), Dst: 192.168.0.105 (192.168.0.105) User Datagram Protocol, Src Port: domain (53), Dst Port: 55129 (55129) Domain Name System (response) No. Time Source Destination Protocol Info 12 37.458709 192.168.0.1 192.168.0.105 DNS Standard query response, Server failure Frame 12 (70 bytes on wire, 70 bytes captured) Ethernet II, Src: AniCommu_c5:4f:19 (00:40:05:c5:4f:19), Dst: WistronI_19:e6:be (f0:de:f1:19:e6:be) Internet Protocol, Src: 192.168.0.1 (192.168.0.1), Dst: 192.168.0.105 (192.168.0.105) User Datagram Protocol, Src Port: domain (53), Dst Port: 36765 (36765) Domain Name System (response) No. Time Source Destination Protocol Info 13 37.459083 192.168.0.105 192.168.0.1 DNS Standard query A debian.org Frame 13 (70 bytes on wire, 70 bytes captured) Ethernet II, Src: WistronI_19:e6:be (f0:de:f1:19:e6:be), Dst: AniCommu_c5:4f:19 (00:40:05:c5:4f:19) Internet Protocol, Src: 192.168.0.105 (192.168.0.105), Dst: 192.168.0.1 (192.168.0.1) User Datagram Protocol, Src Port: 59945 (59945), Dst Port: domain (53) Domain Name System (query) No. Time Source Destination Protocol Info 14 42.451901 66.33.216.127 192.168.0.105 DNS Standard query response, Server failure Frame 14 (70 bytes on wire, 70 bytes captured) Ethernet II, Src: AniCommu_c5:4f:19 (00:40:05:c5:4f:19), Dst: WistronI_19:e6:be (f0:de:f1:19:e6:be) Internet Protocol, Src: 66.33.216.127 (66.33.216.127), Dst: 192.168.0.105 (192.168.0.105) User Datagram Protocol, Src Port: domain (53), Dst Port: 55129 (55129) Domain Name System (response) No. Time Source Destination Protocol Info 15 42.453101 192.168.0.1 192.168.0.105 DNS Standard query response, Server failure Frame 15 (70 bytes on wire, 70 bytes captured) Ethernet II, Src: AniCommu_c5:4f:19 (00:40:05:c5:4f:19), Dst: WistronI_19:e6:be (f0:de:f1:19:e6:be) Internet Protocol, Src: 192.168.0.1 (192.168.0.1), Dst: 192.168.0.105 (192.168.0.105) User Datagram Protocol, Src Port: domain (53), Dst Port: 59945 (59945) Domain Name System (response) <end> Regards, Joel -- Joel Roth -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of "unsubscribe". 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